I understand the concepts behind the terms in the title; however, I have a question about how to transform the wave energy itself. I'm working on a science fair project that involves transforming sound energy into electrical energy--I understand this is not a very reasonable method of harvesting energy, but I figured it does have some use in the real world, and it's a unique experiment to conduct. My plan is to place a series of magnets on a non-magnetized string, and place a copper coil around it. When the sound waves travel along the wire, the magnets will displace longitudinally on the string, and this will form an electromotive force along the copper wire. To capture the sounds, I'm considering using a large cup-like object (similar to how cup telephones work) or even tying the string to a sub woofer. My goal is to maximize the longitudinal displacement of the magnets by increasing the amplitude of the waves. Since there is a definite amount of energy going in to the system, I can not simply increase the amplitude without sacrificing the frequency of the waves. I was wondering if there was any way to modify the frequency so that more of the energy goes to amplifying the sound waves as they travel across the string. Perhaps I could find a way to send certain frequencies so that constructive interference of the waves occurs. I've also considered using resonance amplification by placing two objects near each other (not sure how I should do this) with sound waves coming from one object and being manipulated via the other in order to increase the amplitude. If you have any tips on how to do this, how to have the tension on the string, what kind of magnets to use, how many magnets, etc., please let me know. Also, if you have any modifications for my projects, I will consider each idea. Finally, if you know of a source that contains valuable information of this topic, feel free to post it, and I'll read it for further consideration. Thanks!